^A crater central peak may sit below the mound of sediment. If that sediment was deposited while the crater was flooded, the crater may have once been entirely filled before erosional processes gained the upper hand.[23] However, if the deposition was due to katabatic winds, as suggested by reported 3 degree radial slopes of the mound's layers, the role of erosion would have been to place an upper limit on the mound's growth.[25][26]

^Some of Io's paterae are surrounded by radial patterns of lava flows, indicating they are on a topographic high point, making them shield volcanoes. Most of these volcanoes exhibit relief of less than 1 km. A few have more relief; Ruwa Patera rises 2.5 to 3 km over its 300 km width. However, its slopes are only on the order of a degree.[41] A handful of Io's smaller shield volcanoes have steeper, conical profiles; the example listed is 60 km across and has slopes averaging 4° and reaching 6-7° approaching the small summit depression.[41]